I’m building this printer using the files on the github and the instructios from de RepRap magazine, but iI’m having a problem mounting the pipes, I’ll show you in a photo. I’ve tried changing the long pipes for the short pipes but this way doesn’t work neither.

Hi Daniel,
The pipes are supposed to be under stress in order to provide stability to the frame of the machine. If the top platform leans forward you can trim the long pipes a little to get it level, but it has to feel like a bit of a fight to get the last pipe in because of the tension. Even the Aluminium and stainless steel frame machines have this pre stress, and there the tension is a lot more.